130x-2x^2+20.3=y ; 0
变量x,y满足x-2y=0,x
设Z=X+Y,其中X,Y满足X+2Y>=0,X-Y
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
y=1-x^2 x>=0 ,y=sin|x|/x x
已知x,y满足约束条件:x-y+1>=0,x+y-2>=0,x
设x,y满足约束条件x>=0 x>=y 2x-y
当x、y满足x>=0,y>=x,2x+y+k
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7